Shoe-stiffener



L L. McCLELLAN.

SHOE STIFFENER.

APPLICATION FILED 0411211, 1919.

1,353,968. Patented Sept. 28,1920.

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JAMES L. MGCLELLAN, OF BROOKLINE, MASSACHUSETTS.

' SHOE-STIFFENER.

Specification of Letters Patent.

Patented Sept. 28, 1920.

Application filed October 11, 1919. Serial No. 329,935.

- I To all whom it may concern:

State of Massachusetts,

Be it known that I, JAMES L. MCCLELLAN, a citizen of the United States, residing at Brookline, in the county of Norfolk and have invented new and useful Improvements in Shoe-stiffeners, of which the following is a specification.

This invention relates to blanks adapted to stiffen portions of shoe uppers, such as the toe portion, or the heel portion, or both.

It is now customary to employ a stiffener blank of fibrous material such as felt or textile fabric, provided with a stiffening composition which is adapted to be softened by a moderate heat and to harden by coolin'g, the blank being associated with a shoe upper before the lasting operation, softened by heat, lasted with the upper, and then allowed to harden.

Heretofore the stiffening composition employed has been of such nature that the composition has a tendency to adhere to a sewing needle employed in stitching the blank to the upper, so that the passage of the needle through the stiffener is frictionally resisted, and the needle is gummed and is liable to be broken. Moreover, the nature of the composition heretofore employed has been such that it is liable to stain or discolor upper leather, linings, etc.

My invention has for its chief object to provide a blank obviating the objections above recited, and adapted to be softened by immersion in hot or warm vwater, without absorbing the water.

The invention consists in the improvements which I will now proceed to describe and claim.

In carrying out my invention, I impregnate woolen or other fabric, such as felt, flannel, cloth. etc., with a celluloid-resin solution, constituting a filling which permeates the fabric, the permeated fabric constituting a new article of manufacture having the properties hereinafter described.

I have found that a. filling composed only of a celluloid solution, while free from the abovementioned objections to stiffening compositions heretofore used, hardens too quickly by cooling, so that a stiffener blank containing only a celluloid solution becomes undesirably stifi' before a suitable time is afforded for lasting. To obviate the lastnamed objection, and increase the tensile strength imparted to the fabric by the fillobjection I have succeeded in ing, I incorporate with the celluloid a suitable resin, and

preferably various resins, such as copal, kino, and colophony. A filling composed of this celluloid-resin solution hardens with sufficient slowness, and imparts a desirable tensile strength to the fibrous material.

Celluloid alone, in solution, has a relatively small density, so that a very viscous and thick solution, which can hardly be poured, contains only one pound of celluloid to the gallon: A sheet of fibrous ma terial of sufficient capacity to absorb a gallon of celluloid solution, when impregnated therewith, contains only one pound of solid matter after the solvent has been evaporated out. A stiffener blank cut from the said sheet will be readily softened by heat, but will harden very rapidly in cooling on account of the low specific heat due to the small content of solid material. A solution of cooal having the same viscosity as the solution containing one pound of celluloid will contain approximately ten pounds of copal to the gallon. A sheet of fibrous material impregnated with this gallon of copal solution will contain, after the evaporation of the solvent, about ten pounds of solid matter instead of one pound; consequently, a blank impregnated with the copal solution will have a relatively large content of solid matter, and, therefore, a greater specificheat, so that it will harden moreslowly in coolingp: It has been found, however, that a filling of copal alone is objectionably friable and is liable to crumble to powder, so that the stiffener does not possess the resilience which is desired at the toe and heel portions of shoe uppers.

fter many experiments I have found that the addition of a suitable amount of celluloid to a copal solution overcomes the objections last stated. I have also found that a solution composed wholly of celluloid and copal has a tendency to become stringy and sticky when applied to the fabric. This overcoming by the addition of colophony. The short fibers of this latter material temper the longer fibers of the copal and render the solution less sticky. Kino has the same effect as colophony, and at the same time imparts a pleasing brown color to the solut on, thus giving the blank the appearance of leather. The best and cheapest solvent for d1ssolvand resins is found to be one part of ethyl.

acetate to six parts of denatured alcohol.v

A suitable formula for fiv gallons. the I I softened by hot water.

filling material is as follows;

Six pounds copal, Four pounds colophony,

Two pounds kino,

Two pounds celluloid, Three gallons alcohol,

One-half gallon ethyl acetate.

A sheet of the fabric may be, passed through a bath of the celluloid-resin solution, then between squeezing rolls to express the excess-liquid, then between heated drying rolls to harden the solution, and finally converted by cutting dies into blanks of the desired form, the blanks being preferably skived at their margins.

A blank provided with a filling such as that above described is adapted to be softened by a moderate degree of heat, as by immersion in water at a temperature of about 180 F. The filling is non-adherent to a sewing needle inserted in the stiffener, and does not resist the movement of the needle, so that the needle is not gummed by the filling, and is not liable to be broken during the sewing operation. The filling does not stain or discolor upper leather, lin ings, etc.

The preferred maximum temperature of the drying, rolls employed to harden the filling when the latter is first applied to the fabric is about 212 F. I find that blanks from fabric dried at about this temperature are harder than blanks dried at a lower taaaae, isa' use 170 sad that blanks from fabric dried at the last-named temperature will harden more slowly, and will become less stiff and rigid, after being The accompanying drawing is a plan View 7 of a stilfener for the toe portionof a shoe upper.

Icla'nn'r i 1. As a new article of manufacture, a shoe stiffener consisting of a blank of fibrous absorbent'material, and a filling which consists of a celluloid-resin solution diffused throughout the blank, and adapted to be softened'by a moderate degree-of heat, and to harden by cooling, said filling being nonadherent'to a sewing needle, free from liability to stain upper leather and linings, and rendering the blank waterproof, so that the blank may be softened by immersion in hot water without absorbing the water.

2. A shoe stiffener substantially as speci.

fied by claim 1, said solution including celluloid and colophony. p

p 3. A shoe stiffener substantially as specified by claim 1, said solution including celluloid and kino. d

4. A shoe stiffener substantially as specified by claim 1, said solution including celluloid, colophony, and kino.

5. A shoe stiffener substantially as specified by claim 1, said solution including celluloid, copal, and a resin overcoming friability of copal.

In testimony whereof I have aflixed my signature.

JAMES L. MGCLELLAN. 

